Congestive heart failure (CHF) is a condition where the heart is unable to pump enough blood to meet the demands of the body. There are approximately 5.8 million current patients with CHF in the United States, and an estimated 500,000 new patients emerge each year. Advancements in medical and surgical therapies have significantly improved survival and quality of life, but advanced heart failure patients still experience a mortality rate of 50-75% per year. The standard for treating these advanced heart failure patients is cardiac transplantation, but this is limited to a small number of patients (approximately 2,000 per year) due to donor shortage. As such, left ventricular assist devices (LVADs) have increased in utilization to support this demand by providing either “bridge to transplantation” or “destination therapy” roles. As LVAD designs have improved over the years, they have resulted in significantly decreased mortality and improved quality of life in comparison with optimal medical management. While great advances have been made, LVAD patients still suffer from several procedural and long-term complications directly related to these devices.
The invasiveness of the LVAD implantation procedure itself confers its own potential complications, including significant hemorrhage. The procedure involves an open heart surgery and the institution of cardiopulmonary bypass while the LVAD is sutured to the apex of the heart and the ascending aorta. Since these patients are especially at risk for hemodynamic decompensation, reducing the invasiveness of the procedure is important in preventing instability and death.
One possible solution to significantly minimize the invasiveness would be the utilization of percutaneous endovascular techniques, where a miniaturized device could be inserted into a blood vessel near the skin and guided to the heart using real-time x-ray images, avoiding the need for open heart surgery. The Impella 2.5 (Abiomed) is a temporary left heart pump that can be inserted through the femoral artery and guided to the left ventricle in this manner. It is approved for providing short-term partial circulatory support up to 6 hours. While useful for short-term application, its inherent design prevents its application for long-term implantation equivalent to current LVADs. The Impella 2.5 includes a motor that is attached to an impeller and lacks a complete seal so that the shaft of the motor is able to spin. Thus, in addition to the power line exiting the femoral artery, an additional percutaneous line containing glucose purge fluid must be connected to the motor to overcome the pressure of blood from entering the motor unit.
Additionally, percutaneous LVADs are limited by the small diameter of the vessel used for introduction. For instance, the percutaneous Impella 2.5 requires extremely small impeller blades and is thus limited to a flow rate of 2.5 L/min. Moreover, these small designs require the motor to spin at a high speed, resulting in increased heating of the motor which can create the need for a cooling solution if used over the long-term. Some efforts, such as the Percutaneous Heart pump from Thoratec, have employed elastic impellers to attempt to overcome this small vessel limitation. However, these flexible materials may not provide sufficient durability for long-term use if they are constantly deflecting blood at 10,000-30,000 revolutions per minute as compared to durable materials found in traditional impellers, made of materials such as titanium.
Thus, there is a need in the art for devices, systems and methods that provide long-term LVAD function while reducing the invasiveness and dangerous risks of the current implantation procedure. The present invention satisfies this unmet need.